WASHINGTON — A federal grand jury on Wednesday indicted the suspect in the foiled Christmas Day airline bombing on six criminal counts that could bring a life sentence if he's convicted.

In a seven-page indictment, a grand jury in Michigan charged that Umar Farouk Abdulmutallab, a 23-year-old Nigerian, attempted to use "a weapon of mass destruction" by starting a fire with explosive chemicals he'd smuggled onto Northwest Airlines Flight 253, which was carrying 289 other passengers and crew members to Detroit.

"The attempted murder of 289 innocent people merits the most serious charges available, and that's what we have charged in this indictment," said U.S. Attorney Barbara L. McQuade, the U.S. attorney for the eastern district of Michigan.

The other charges against Abdulmutallab are attempted murder, attempted destruction of the aircraft, placing a destructive device aboard the plane and two counts of possessing a destructive device.

A Justice Department spokesman said that Abdulmutallab, who's in federal custody, would appear in the U.S. district court in Detroit at 2 p.m. Friday to be arraigned.

Investigators say Abdulmutallab told them he was acting on orders from an al Qaida-affiliated group by igniting a fire shortly before the plane landed in Detroit on Dec. 25. He set his pants legs and the wall of the plane ablaze before passengers subdued him and smothered the flames, according to witnesses.

In an earlier criminal complaint, the Justice Department said the bomb contained pentaerythritol, a colorless, organic compound that's similar to nitroglycerin. The indictment announced Wednesday said it also contained triacetone triperoxide, a relatively easy-to-obtain explosive and a weapon of choice for suicide bombers in the Middle East, according to the independent Web site Globalsecurity.org.

Failed "shoe bomber" Richard Reid also used both explosives. Passengers on an airliner subdued him in December 2001 while he was trying to ignite PETN in his shoe.

"The bomb was designed to allow defendant Umar Farouk Abdulmutallab to detonate it at a time of his choosing, and to thereby cause an explosion aboard Flight 253," the indictment charges.

Attorney General Eric Holder said that the investigation "has already yielded valuable intelligence that we will follow wherever it leads."

The incident aboard the flight, which originated in Amsterdam, has restarted a massive debate over air security, including the use of controversial body-scanning devices at airports.

Homeland Security Secretary Janet Napolitano said that 300 additional whole-body scanners would be in place at U.S. airports by the end of the year, compared with 40 today. Proponents argue that the devices could have detected the explosives that Abdulmutallab is accused of carrying, while critics say they're an invasion of passengers' privacy.

Speaking on CNN, Napolitano said that the scanners, which cost about $170,000 each, were worth the investment.

"Look, we can't give 100 percent guarantees here," Napolitano said. "I don't think Americans disagree with that. They understand that. But they also understand and we understand that improved technology can help minimize the risk, and that's what these scanners assist us in doing."